1. Field of the Invention
This invention relates generally to sawhorses for supporting carpentry and like work in progress at a convenient level for cutting, etc., and more particularly to a folding sawhorse frame for use with a disposable top member that actually supports the work.
It is not required that the top member in fact be disposable, but the invention is in the field of frames that permit use of an inexpensive piece of lumber or other stock for the top member; and in particular the top member may be somewhat warped or otherwise irregular and yet serve the purpose.
2. Prior Art
Earlier sawhorses have for the most part been made of wood, nailed together.
Some barricades have been made in generally sawhorse-style configuration, constructed partially or entirely of metal, with a hinge pin at each end near the top. Generally these prior sawhorses have a "built-in" or integrally incorporated work-supporting top member that is a permanent part of the sawhorse structure.
Nailed-together wooden sawhorses suffer from the disadvantage that when the work-supporting top member that runs along the top of the sawhorse has become badly cut, pitted, or scarred by virtue of tools passing entirely through the actual work and into the top member, it is at best very inconvenient to replace the top member. Generally the whole sawhorse must be disassembled and a new top piece nailed into place.
It is often difficult to use a top piece that is not fairly straight, since a crooked or twisted top section may make the whole sawhorse crooked or twisted to the extent that it does not stand firmly on the floor.
Moreover, such sawhorses are somewhat heavy to move around, and awkwardly bulky to store when not in use. Most importantly, as such a sawhorse ages, its fastening nails begin to loosen and it tends to become more and more "rickety" or unstable, confronting the user with the decision whether to build a new sawhorse, attempt to reinforce the old one, or just put up with the instability for a while longer.
Substituting metal for wood in a conventional sawhorse presents the problem of manufacturing cost, particularly because a sawhorse must be quite sturdy to be of any value at all. Carpentry often involves the carpenter's placing her or his own weight, as well as the weight of the workpiece and tools, on the sawhorse; and it is essential that the sawhorse not buckle under these loads. Use of conventional sawhorse configuration, involving a number of different-sized pieces for bracing, therefore would be quite costly in metal, and would of course--just as in wood--produce a rigid structure awkward to move and to store.
Moreover, an all-metal sawhorse would be subject to the disadvantage that tools passing all the way through the workpiece would impinge upon a metal top member, very likely to damage or at least hasten the wear on the tools. In many situations this arrangement also would invite tool slippage or rebound, damaging to the workpiece and/or hazardous to the carpenter.